1. Field of the Invention
The present invention is directed generally to a valve assembly, and more specifically, to an adjustable rotary valve assembly for selectively controlling the flow of a fluid and a fluid-flow process including said rotary valve assembly.
2. Description of Related Art
Previous valve assemblies are of limited use for fluid flow applications because of their lack of flow-control adaptability, reversal or metering. Generally, prior art processes employ numerous separate valves and sophisticated electronics to control the cooperation of those valves to bring about a desired process fluid flow control. This need for multiple valves and control circuitry to coordinate the operation of the many valves made process fluid control complex and expensive.
For example, storage of cigars at a proper relative humidity is essential for preservation of quality and flavour. Generally, cigar manufacturers recommend storage between 60% and 70% relative humidity, with preferably greater than 63% and less than 68% relative humidity. Cigar storage outside these generally accepted limits may be detrimental to flavour, draw, burn and other favourable characteristics. Cigar storage in a control environment such as a humidor generally made of moisture absorbing wood, such as Spanish Cedar or Mahogany maintain freshness of cigars without imparting undesirable flavours measurement of relative humidity is generally by means of mechanical hygrometer and/or chemical or electronic moisture sensor.
Humidity maintenance within a humidor can be active or passive. Active humidity control uses a humidity sensor as feedback to a fan circulating air over a moisture source. Relative humidity lower than a set point results in evaporation of water and increase in humidity within the humidor. One limitation to such a humidifier system is an inability to remove excess moisture. If the relative humidity within a humidor is greater than desired, humidifier only systems provide no relief. Passive humidity control systems do not provide circulation within a humidor and use physical-chemical properties of materials, e.g., propylene glycol solutions, silica gel, salts and other compounds to regulate relative humidity in stagnant air. Changes in relative humidity within a humidor, i.e., either increase or decrease result in acceptance or rejection of water to maintain an equilibrium with air. These materials have an ability to both to acts a both humectant and desiccant. Limitations of passive materials, mixtures and/or solution result from constant equilibrium humidity at constant solution concentrations, mixture proportions or moisture content, an equilibrium relative humidities may be higher or lower than desired and as these materials, solutions and/or mixtures modulate humidity within a humidor the equilibrium relative humidity may change. Thus, both active and passive systems have significant shortcomings, and systems employing a multitude of conventional valves is impractical due to cost and complexity.
According to another example, conventional in-home oxygen concentrators have sophisticated designs capable of providing purity or oxygen at 95% or better, variable oxygen flowrates up to six liters per minute, reliable components and warranty of five years or more and ease of product maintenance.
The number of components in an in-home oxygen concentrator can exceed one-hundred. In general, systems include an air compressor, and a typical valving scheme including many independently-controlled valves to direct gas flow in conduits, several separate process fluid flow conduits, check valves, tubing connectors, fittings and the like are necessary as well as a heat exchanger to expel compressive heat, a fan to circulate cooling air and disperse oxygen deplete air, an intake air and output bacterial filter are all fit within a cabinet enclosure with control panel. A flow valve regulates patient flow and in some cases electronic circuitry controls process cycle time and process step time. The in-home oxygen concentrator generally consumes about 400 watts electrical power, emits 40 to 48 decibels relative sound pressure, weighs nearly 60 pounds and occupies at least two cubic feet of volume.
Accordingly, there is a need in the art for a valve assembly that can be adjusted to provide variable cycle times and process step time, for example. The valve assembly can be a low-cost, simple design that can be operated manually, semi-automatically, automatically, or any combination thereof, as desired. Alternately, the valve assembly can optionally permit variable process fluid flow directions without requiring changes to existing process plumbing configurations.